Question

Newsela: Growing Microorganisms in a Petri Dish
What is the purpose of the control Petri dish in the experiment?
a. to test if the gelatin medium is effective
b. to see if microorganisms grow without any added samples
c. to compare the growth of microorganisms from different sources
d. to measure the temperature of the environment

Answer 1

The purpose of the control Petri dish in the experiment is:

b. to see if microorganisms grow without any added samples.

The control dish helps establish a baseline for comparing the effects of the added samples in the experimental groups.